Article Abstract:
A Bacillus sphaericus monooxygenase capable of catalyzing the first two steps in the degradation of p-nitrophenol (PNP) via 4-nitrocatechol and 1,2,4-trihydroxybenzene (THB) was identified and characterized. Nitrite was produced stoichiometrically by PNP-grown cells. Results of the THB stimulation of oxygen consumption reveal that THB acts as a substrate for a ring cleavage dioxygenase. It was also observed that a single monooxygenase system was capable of catalyzing the initial hydroxylation of PNP and the oxidative release of the nitro group from the 4-nitrocatechol.
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Article Abstract:
Gnotobiotic piglet model is used for investigating the virulence of isolates from healthy cattle and from humans in disease outbreaks and also for determining the correlation between production of Shiga toxin 1 (Stx1) and Stx2 and virulence. The studies have shown that disease outbreaks select for producers of high levels of Stx2 among Escherichia coli O157:H7 strains shed by animals and that Stx1 expression is not important in human outbreaks.
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Article Abstract:
A recombinant plasmid carrying nitrobenzene (NB) nitroreductase (nbzA) and hydroxylaminobenzene (HAB) mutase A genes is constructed and the enzymes in Escherichia coli JS995 are expressed. The biocatalytic production of ortho-aminophenols from nitroacetophenols suggests that strain JS995 might be useful in the biocatalytic production of a variety of substituted ortho-aminophenols from the corresponding nitroaromatic compounds.
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